As you say, an extreme situation - and in practice won't happen. In part, that's why I suggested a large number of loads. Most large domestic loads are a) controlled and b) not in any way synchronised. So while the network load will not be constant, I expect it'll follow a fairly narrow spread centered around the average.
... at a particular time of day, yes. However, as I said, although I haven't yet had a chance to investigate the theory, I suspect that things might gradually move (a little!) in the direction of that extreme as one moves away from a situation in which the total of loads is essentially the same throughout the 24 hours of the day - such that the 'energy loss benefit' of increasing voltage over a whole day might be less than your calculations would suggest.
BUT, I suspect things may start changing with the pressure to move to smart demand management. So potential for large amounts of loads all turning on when a cheap charging period starts.
Is not the whole idea of 'smart demand management' to attempt to even out demand over the 24 hours of a day? If so, per the above, it would/will probably move us closer to the 'ideal' situation as regards the effect of voltage changes on energy loss?
No, not always. It varied on what was available locally, through to the 1970's - maybe even later. Wholesalers, and lamp sellers, stocked a variety of lamp wattage and voltages.
Thanks Harry. yes power was derived from more local sources and as such could vary a bit in the way it was produced. I was talking "always was" etc as being during my lifetime as far as I was aware which is more of a snapshot in the scheme of things really . My own perception of our mains voltage probably reflects a time from the early 70s plus or minus a bit and the area where I had always lived, to present day being a perception of "always" to me personally. Approx when I started my working life.
It was wrong of me to use the term always in such a way really rather than in my own blinkered experience.
I was trying to convey that nothing has really changed from our declared voltage of 240 to our modern declared voltage of 230 , it is still really not changed physically but just in the way we now declare.
Personally I think the change in declared voltage was probably a good idea being the best of many.
I am aware that some people think we have actually lost about 10 volts these days when really we have not.
Particularly given that, as you say, little (if anything!) has changed physically as a result, what was sufficiently 'broken' about the previously declared 'nominal voltage' to require it to be 'mended'?
Nothing really, but we were on 240V I think one or two might have been on 230 and a few were on 220 as one of their common voltages so a midish point like 230 and open up the limits a bit harmonises the voltage band an gets manufactures to ensure their goods work across the whole continent and further afield too therefore a nice tidy up.
Next stop - The World - 1000V - plus or minus 100% and we have cracked it - mankind is unified .
We might just need to waith a few years for that one though
Nothing really, but we were on 240V I think one or two might have been on 230 and a few were on 220 as one of their common voltages so a midish point like 230 ..
If (as was the case) 'most' were around 240 V and 'one or two' (or 'a few') were on 230 V or 220 V (and presumable a few nearer to 250V), then I wold have thought that the "midish point" would be much closer to 240 V than 230 V, wouldn't it?
... so, not really 'broken', so not really needing mending
Next stop - The World - 1000V - plus or minus 100% and we have cracked it - mankind is unified .
We might just need to waith a few years for that one though
Realistically you don't need a range quite that wide. 100V to 240V nominal covers pretty much any mains supply in the world. Add say 10% tolerance bands to that and you get something like 90V to 264V.
For electronics with switched-mode power supplies, this input range is easily achievable. Not so easy for things that run directly off the mains.
Realistically you don't need a range quite that wide. 100V to 240V nominal covers pretty much any mains supply in the world. Add say 10% tolerance bands to that and you get something like 90V to 264V.
Indeed - in terms of "pretty much any mains supply (currently) in the world.
However, I thought this discussion had evolved into one about the potential energy savings (reduced losses in DNO LV network). That would obviously favour higher voltages than current ones. That might raise some 'safety issues', but I'm not convinced that, say, 400 V would, in practice, be any more dangerous than 230/240 V, given that the latter is already plenty high enough to kill.
My choice of 1000V +/- 100% was purely to better illustrate the absurdity of opening up the voltage band too high . I think a notational change of about 4% such as in the UK and similar amounts in Europe was a good example of a "fudge" that could/pretty much does workout in practice - but take it too far and we could run into real problems though.
I presume you mean what is known as "wild leg" or "high leg". You take a 3 phase delta secondary and ground the midpoint of one of the windings. So you effectively have a 120V/240V split phase supply combined with a 240V three phase supply.
The pros are it gives you 120V single phase, 240V single phase and 240V three phase from the same supply. The cons are it's difficult to balance because all your 120V and 120V/240V loads end up on the same phase, only pure 240V loads can be properly balanced between the phases.
The impression I get is it's falling out of favour in favour of 120V/208V wye (aka star) supplies.
Wild Leg ? not heard that before, thanks, High leg yes I heard that so I said dog leg, easy to remember I think. Yes it is a bit puzzling to us, mind you our ring final puzzles a lot of the world I think so pot kettle black to call any of theirs I suppose. I wonder why they chose 60Hz against our 50Hz ?
I suppose we can a bit understand our driver sits on the right but their driver on left and cars on the right goes against whirlwind attraction defence so I heard (could be a load of boudlrdollocks though, I also tried that water down plughole thing both here and in Oz and seems to make no discernible difference either
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